Figure 3

Wound collagenase expression peaks earlier in castrated rats. (a) Day 2 and 6 wound tissue from intact and castrated rats was analysed immunohistochemically for MMP-1 (upper panels) and MMP-13 (lower panels) protein expression profiles. MMP-1 was highly expressed by epidermal keratinocytes (KC) and infiltrating inflammatory cells (IC) in day 2 and 6 wounds in intact and castrated animals (intact shown); MMP-13 solely by keratinocytes. (b) Overall numbers of day 2 and 6 wound MMP-1-immunoreactive non-epithelial cells were unaffected by castration. (c, d) In castrated rats, overall wound MMP-1 and MMP-13 protein levels were increased on day 2 post-wounding and decreased on day 6. (e) Expression of the genes, which encode both MMP-1 and MMP-13 tended to be reduced in day 2 wound tissue from castrated animals (in the case of the Mmp1a gene, the decrease was statistically significant). (f) Overall wound collagenase activity (in units (U) per μg of total wound protein, where 1 U represents the cleavage of 1 μg of collagen per minute) was significantly decreased in castrated animals on day 6 post-wounding. n=5–7 per treatment group. Data are expressed as mean±s.e.m. ^*P<0.05 (intact vs CSX). Scale bars define a distance of 25 μM. Arrows identify positively stained cells.